I'm no professional, but...
I liked this song. I'll start with the bad first. The cymbals bothered me for some reason. I think it needed more high hat. I dunno, something. My only other complaint is that it seemed a bit repetitive for about a minute in the middle of the song.
Now onto the good. Great transitions. nuff' said there. Also, the choice of instruments was excellent and the mixing was great as well. It's easy to see..rather hear that you spent a good bit of time on this song. The effects that you chose to use were nicely implemented.
Overall, I'd say that this song was well thought out and nicely executed.
good stuff.